Radiation Damage to Cell Molecules

Target Theory

• Cells contain many species of molecules, most of which exist in excess, making them less susceptible to radiation damage.
• However, some molecules are essential for normal cell function and are present in limited quantities, making them vulnerable to radiation damage.
• Radiation damage to these critical molecules can severely affect the cell because there are no substitutes available.
• The target theory is based on the concept of a sensitive key molecule that must be inactivated for a cell to die after radiation exposure.
• DNA is considered the target molecule.

Target Molecule

• The target molecule is an area of the cell occupied by the molecule or a sensitive site on the molecule.
• The target area changes position over time due to intracellular molecular movement.
• The interaction between radiation and cellular components is random, with no preference for the target molecule.

Radiation Interaction

• When radiation interacts with the target molecule, it is considered a "hit."
• Radiation can also interact with molecules other than the target molecule, resulting in indirect effects.
• It is not possible to distinguish between direct and indirect hits.
• Hits occur through both direct and indirect effects of radiation.

This quiz is about the effects of radiation damage on cell molecules, particularly the impact on essential molecules for normal cell function.